It has been postulated that if hemispheric specialization fails to develop in man, serious cognitive defects may result. Recent electrophysiological studies by the Principal Investigator suggest that a defect in the development of hemispheric specialization may underlie some of the more serious handicaps of the autistic child. In the latter investigation, which was carried out in sleep, normal children were noted to have larger auditory evoked responses (AERs) to 'click' stimuli over the right hemisphere in comparison to the left. Autistic children were found to be significantly lacking in this AER inter-hemispheric difference. In the present investigation it is proposed to further develop a methodology and a technique whereby AERs may be employed to study hemispheric specialization in man in the waking state. Linuistic and musical-chord stimuli will be delivered randomly to the right or left ear, and the inter-hemispheric differences in amplitude, latency and power-spectra of the auditory evoked responses will be studied as a function of type of stimulus, stimulated ear, and location o$ the recording electrodes on the scalp. Once the technique has been developed and prfected it is hoped that auditory evoked responses may be used in future projects to study the development of hemispheric specialization during childhood and to discover whether deficiencies in the development of hemispheric sppcialization may be present in one or other of the developmental disability syndromes including early infantile autism.